Author Topic: 4 channel Keysight 1000x series scope  (Read 31090 times)

0 Members and 2 Guests are viewing this topic.

Offline martinot

  • Regular Contributor
  • *
  • Posts: 79
  • Country: se
Re: 4 channel Keysight 1000x series scope
« Reply #125 on: July 10, 2020, 10:54:07 pm »
You are missing one very important point, the idea is not to capture all 50000 packets with a scope to do an analysis.  A logic analyzer is better suited for such capture and analysis.  The point I was trying to make is that by triggering 50000 times, it can capture a specific event and the Siglent will probably miss it.  That is the whole point of using the protocol analyzer on the scopes.  My SPI test setup has a user button enabled that sends a specific packet 0x3F when pressed, and 0x37 when not pressed.  The KS gets it almost on every click, but the siglent misses a lot of them, the SDS1104X-E that I tested missed like 80-90% of them.  Even the GDS-1054B can trigger on 90-100% of the time, the siglent is very slow handling serial decoding and triggering.

When scope is armed and waiting for trigger (in Normal not Auto mode), it will trigger instantaneously. It is literally waiting to pull the trigger. It is retriggering that is questionable, once it triggers and finishes the sweep, it will take time to rearm. That rearm time is very fast on Keysight, also very fast on new Rigols , and a bit slower on Siglent. And because of it, Keysight might trigger on every packet and Siglent might not be ready for next one and miss it...


Yes, that looks like a reasonable explanation.
 

Offline Bud

  • Super Contributor
  • ***
  • Posts: 6877
  • Country: ca
Re: 4 channel Keysight 1000x series scope
« Reply #126 on: November 11, 2020, 06:41:12 am »
Firmware for the DSOX1204x series is now posted on the Keysight website. As this scope runs linux it should be interesting to take a peak at.

Shouldn't be mission impossible to devise workarounds... ;)

The .ksx is a initrnamfs file which can be easily opened with 7zip decompressor.
There is a 128 byte sw-description.sig file.  Anyone knows how it is generated?  It is different on each install package (.ksx)

Sounds like a 1024-bit RSA signature to me. Must be generated using a private key at the factory and verified with the public key residing inside the scope during software setup.
Facebook-free life and Rigol-free shack.
 

Offline Bud

  • Super Contributor
  • ***
  • Posts: 6877
  • Country: ca
Re: 4 channel Keysight 1000x series scope
« Reply #127 on: January 01, 2021, 01:02:41 am »
Some additional info:

- Firmware package description file sw-description is signed with a 1024-bit RSA key. The signarure is in sw-description.sig file. It can be verified using the following parameters:
      Algorithm:   RSASSA_PKCS1
      Hash:    SHA256
- The assumption is the signature will be verified during firmware update by the scope using the corresponding public key stored in the previous firmware. A copy of the public key is also shipped in the firmware update (a copy is attached). Technically, every time the firmware is updated, a new public key can be shipped for the next firmware update. Signing the firmware update package prevents the firmware files from being altered.
- Root account is disabled.
- The working account is called 'tlouser'. The password for it is stored as SHA-512 hash with salt.
- The filesystem is stored compressed and is of read-only type
- NAND flash memory size is double of that on 1000X (256MiB vs 128MiB)
Facebook-free life and Rigol-free shack.
 
The following users thanked this post: TK

Online tv84

  • Super Contributor
  • ***
  • Posts: 3212
  • Country: pt
Re: 4 channel Keysight 1000x series scope
« Reply #128 on: January 01, 2021, 10:10:55 am »
- The assumption is the signature will be verified during firmware update by the scope using the corresponding public key stored in the previous firmware. A copy of the public key is also shipped in the firmware update (a copy is attached). Technically, every time the firmware is updated, a new public key can be shipped for the next firmware update. Signing the firmware update package prevents the firmware files from being altered.

Correct BUT they usually keep always the same key because, if you would change key from package to package, when doing an update an user would be forced to execute all intermediary updates between his version and the current version. Also, KS would be forced to make available all those packages in their website, etc. permanently.

So, they can do a key change but only when there is a major justification for that and, then, everyone will have to go through that update package.
 
The following users thanked this post: TK

Offline Bud

  • Super Contributor
  • ***
  • Posts: 6877
  • Country: ca
Re: 4 channel Keysight 1000x series scope
« Reply #129 on: February 23, 2024, 04:11:10 pm »
The story continues here.
Facebook-free life and Rigol-free shack.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf